Fix docs gh-pages push hanging until job timeout

[atalman]

Summary

The upload job's docs push to gh-pages has been hanging until the 60-minute job timeout on tag/main pushes (deterministic, not a flake): both the v0.27.0 and v0.28.0 runs show build succeeding and upload cancelled ~59 min into a silent git push. Automated pytorchbot "auto-generating sphinx docs" commits on gh-pages stop at 2026-01-21; every release since was pushed manually.

Root cause

The git push runs inside the build container (repo mounted at /pytorch/vision). actions/checkout stores the auth header in a temp file wired via path-scoped includeIf.gitdir for the runner-host path and /github/workspace/... — neither matches /pytorch/vision/.git. So the push is unauthenticated; with a TTY and no credential helper, git blocks on an interactive credential prompt until the timeout.

Fix — this authenticates the push so it succeeds

The real fix is giving the push valid credentials. SECRET_GITHUB_TOKEN is already present in the container and the job has contents: write, so we push with an explicit token:

export GIT_TERMINAL_PROMPT=0
git push "https://x-access-token:${SECRET_GITHUB_TOKEN}@github.com/pytorch/vision" HEAD:gh-pages

GIT_TERMINAL_PROMPT=0 is only a safety net (turns any future auth problem into an immediate error instead of a 60-min hang); the authenticated URL is what makes the push actually complete.

Verification that the push succeeds (not just fails fast)

• The tokenized-URL form authenticates against pytorch/vision: git ls-remote https://x-access-token:<token>@github.com/pytorch/vision gh-pages returns the ref, no prompt.
• gh-pages is not a protected branch, and the token has push/contents: write, so the push is authorized to write.
• SECRET_GITHUB_TOKEN is confirmed populated in the container (the failing 0.28 run logged ALL_SECRETS: {"github_token":"***"}), and run_with_env_secrets.py exports it as SECRET_GITHUB_TOKEN.
• After merge, the first push to main will exercise this path and should land a fresh auto-generating sphinx docs commit on gh-pages within minutes (instead of timing out) — the authoritative end-to-end confirmation.

AI assistance (Claude) was used for this change.

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/vision/9548

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 2 Pending, 2 Unrelated Failures, 1 Unclassified Failure

As of commit b9cd225 with merge base 66089cf ():

UNCLASSIFIED FAILURE - DrCI could not classify the following job because the workflow did not run on the merge base. The failure may be pre-existing on trunk or introduced by this PR:

• .github/workflows/pr-labels.yml (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• Build M1 Wheels / pytorch/vision / build-wheel-py3_10-cpu (gh) (trunk failure)
  Process completed with exit code 1.
• Build M1 Wheels / pytorch/vision / upload / upload-wheel-py3_10-cpu (gh) (trunk failure)
  Unable to download artifact(s): Artifact not found for name: pytorch_vision__3.10_cpu_

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